Patent GB-231474-A (GB)
Title: Improvements in or relating to apparatus for the electrical transmission to a distance of writings or drawings
IPC: G08C21/00
Filed: 1925-03-19
Abstract: 231,474. Soc. Anon. Teleautografi Midali. March 26, 1924, [Convention date]. Void [Published under Sect. 91 of the Act]. Writing-telegraphs.-In a system in which the displacement of the stylus at the transmitting station along each of two perpendicular axes is transmitted through mechanism to the rotor of a corresponding asynchronous motor at that station, and the resulting current in each of the two rotors is transmitted to the opposed winding of the rotor of a corresponding motor at the receiving-sbation thus effecting a similar movement and the displacements of the reproducing stylus are effected through mechanism from the two rotors at the receiving station, the mechanism at each station comprises sector and lever devices. The apparatus, which is similarly arranged at the two stations, is shown in plan in Fig. 1, and is operated as follows. Normally the stylus 29, Fig. 12, at each station is supported by the armature 28 of an electromagnet 27, and is in raised position over a push-button C. A switch member M is first moved by the operator at the transmitting station from the position b to position a, Fig. 12, to break a short circuit of two contacts 32, 33 normally held apart by a spring. A member 31 is then momentarily depressed to close the circuit at these contacts, thus short-circuiting a resistance Rs in the rotor circuit of the motor A at each station, and the increase of current in each rotor circuit is sufficient to enable the relay R to close the circuit of the magnet 27 to lower the stylus 29. The stylus at each station thus bears on the push-button C, and closes the circuit of call signal 41 until the member 31 is released. The stylus 29 at the transmitting station is then brought over a push-button AC and the member 31 is again momentarily depressed. Each stylus thereupon depresses the corresponding button AC to close a circuit through a solenoid 19 at the same station, and a rack 20 on the armature thus attracted actuates a pinion 21 driving rollers for unwinding paper from a drum to place a fresh portion of the roll on each writing table. The transmitting operator now removes the stylus 29 from the armature 28, introduces its point into a hole provided in the member 1, and lowers it on to the paper. This movement shortcircuits the resistance Rs and thus effects the lowering of the stylus at the receiving station. As the operator writes the message, the movement of the stylus along each of two perpendicular axes is transmitted through the mechanism shown in Fig. 1 to the rotor of one of the. motors A or B, the resulting currents are transmitted over the line wires i', i<2> to the receiving station thus effecting similar movements of the rotors of the corresponding motors to actuate the reproducing stylus. The mechanism includes a toothed sector 4 on a shaft 15 carrying a support in which slides a bar 18 carrying the member 31. When the writing is completed a push-button TC is depressed to actuate a knife for detaching the paper bearing the writing. A push-button switch T is provided at each station to enable a telephone to be connected to line in placa of the writing telegraph.